Note: Descriptions are shown in the official language in which they were submitted.
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SPACER WITH STRETCHABLE SHEATH
FIELD OF THE INVENTION
The present invention relates to spacers for maintaining structures in a
spaced
relationship and is more particularly concerned with a spacer having a
stretchable sheath.
BACKGROUND OF THE INVENTION
Concrete pipe and similar reinforced products, such as manholes, box sections,
catch basins, septic tanks and the like, are conventionally manufactured by
positioning a reinforcing structure, such as a reinforcing metal mesh cage or
the
like, within an a first, outer mould. A settable mixture, such as concrete, is
then
distributed within the mould in a space bounded by a mould inner surtace of
the
mould to form the product. For example, in a so-called dry cast process, a dry
settable mixture is introduced into the mould and distributed therein by
subjecting the settable mixture to heavy duty vibration, packing, or spinning.
The mould is then removed. However, the structure must be retained in a fixed
retaining position during the distribution in order to provide a product of
sufficient strength and to ensure that parts of the structure are not unevenly
placed within the product and that they do not protrude outwardly therefrom.
This requires maintaining the structure within the space in a spaced
relationship
with regard to the mould inner surface of the outer mould during distribution
of
the settable material.
In order to maintain the spaced relationship, recourse is typically had to
spacing
means, commonly referred to as a spacer. Spacers are typically engaged upon
the structure during distribution of the settable mixture and retain the
structure in
the retaining position with regard to the mould inner surtace. Thus, the
spaced
relationship is maintained.
The aforementioned use of spacers in the manufacture of reinforced products is
well known and a number of different spacers have been proposed in the prior
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art. For example, one or more spacers having outward protrusions can be
attached to the structure prior to placement in the mould, the spacer being
completely enclosed within the mould when the structure, with spacers
installed,
is within the mould. The outward protrusions of the spacer, which extend
therefrom toward the mould inner surface, engage the mould inner surtace
when the structure is inserted therein and maintain the positioning of the
structure and the spaced relationship.
United States patent No. 4,989,388 discloses such a spacer, where the spacer
is formed of a continuous piece of round spring-steel wire and has a closed
loop
formed at one end that hooks on a wire of the structure, namely a metal mesh
cage. The closed loop connects two parallel spaced-apart legs that provide a
spacing nose, i.e. the outward protrusion, the legs terminating at the other
end
of the spacer in an S-shaped hook that snaps over another of the wires of the
cage. The spacing nose engages the inner surface of the mould and maintains
the spaced relationship. However, spacers of this nature often require manual
placement of a significant number of spacers on the structure prior to
insertion
of the spacer in the mould. This is cumbersome, time consuming, and labour
intensive, and therefore expensive. Further, the spacer remains permanently
attached within the product, thereby engendering a risk that the spacer may
protrude outwardly from one or more surfaces of the product, thus possibly
impeding manufacture of a product having a smooth surface. In addition, the
spacer can not be re-used, which further increases costs as new spacers must
be used every time the mould is used to manufacture another product.
United States Patent No. 5,236,322 discloses a re-usable spacer for a concrete
pipe product making machine having a mould for forming the product, namely a
concrete pipe. The spacer is installed on an outer surface of the mould,
opposite the inner surface surrounding the structure, and has an extension
means, namely a piston, for extending a retaining member, i.e. a blade,
disposed in a cylinder assembly. The piston is connected to the blade and
moves the blade through a passageway, defined by an outer opening on a
mould outer surface of the mould and an inner opening on a mould inner
surtace of the mould, to a retaining position for retaining the structure in
the
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desired spaced relationship and for retracting the blade into a retracted
position
in which the retaining member is integrally retracted from the space bounded
by
the mould inner surface after the distribution of the settable mixture. Since
the
retaining member is retracted and the spacer is not disposed on the inner
surface of the mould, the spacer can be re-used. United States Patent
Nos. 4,710,115 and 4, 505,658 also disclose re-usable spacers attached to the
outer surface of the mould and that use retaining members inserted through a
passageway to retain the metal mesh cage structure in position.
While the reusable spacers taught by United States Patent No.4,710,115,
United States Patent No. 5,236,322, and United States Patent No. 4,505,658 at
least partially address the question of re-use, they are vulnerable to the
possibility that the settable material will flow into the mould inner opening,
notably near the edges thereof, and thus outside the space bounded by the
mould inner surface. Flow of the settable mixture outside the space though the
mould inner opening may cause an uneven distribution of the settable mixture,
especially around the mould inner surface, thereby engendering unwanted
protrusions , such as ridges, on the surface of the product near the mould
inner
opening, especially when a smooth surface for the product is desired. Further,
an uneven distribution of the settable mixture may create areas of relative
weakness within the product, possibly reducing product life.
Accordingly, it would be advantageous to have a re-usable spacer that is
easily
and economically fastened to the mould on the mould outer surface thereof and
which prevents flow of the settable mixture outside the space defined by the
mould inner surface of the mould.
SUMMARY OF THE INVENTION
The present invention provides a spacer and sheath therefor that furnish
numerous advantages. Firstly, sheath advantageously prevents formation of
ridges and allows for formation of a product having a smooth product outer
surface, without ridges or other protrusions, defined by a first mould inner
surface that surrounds a structure, such as a metal mesh cage, of a first
mould
and a sheath. In addition, the spacer is fastened to a first mold outer
surface of
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the first mold and is thus re-usable. Further, the spacer has adjustment means
for adjusting the spaced relationship of the structure in relation to the
first mold
inner surface.
In one aspect, the present invention provides a spacer for retaining a
structure
in a spaced relationship relative to a smooth first mould inner surface of a
first
mould, the first mould inner surface generally surrounding the structure and
having a first mould inner opening extending at least partially inwardly into
the
first mould, during distribution of a settable mixture within a space within
the first
mould, the spacer comprises: a stretchable sheath for impermeably covering
the first mould inner opening, the sheath stretching into the space towards
the
structure and retaining the structure in the spaced relationship when a
retaining
force for retaining the structure in the spaced relationship is applied to the
sheath, the sheath substantially smoothly aligning with the first mould inner
surface to smoothly bound the space therewith when the retaining force is
withdrawn for preventing a flow of the settable mixture outside the space
through the first mould inner opening.
In another aspect, the present invention provides a stretchable sheath
disposed
between a retaining member of a spacer and an inner opening of an inner
surface of an outer mould, the inner opening being impermeably covered by the
sheath and extending at least partially inwardly into the outer mould, the
sheath
stretching and enveloping the retaining member when the retaining member is
extended through the inner opening into a retaining position for retaining a
structure in a spaced relationship relative to the inner surface during
distribution
of a settable mixture within a space within the first mould, the sheath being
substantially aligned with the first mould inner surface and smoothly bounding
the space therewith when the retaining member is integrally retracted from the
space into a retracted position, the sheath preventing a flow of the settable
mixture outside the space through the inner opening.
In still another aspect, the present invention provides a method for
preventing
flow of a settable mixture outside of a space within which a settable mixture
is
distributed while maintaining a spaced relationship of a structure relative to
a
first mould inner surface of a first mould, the first mould inner surface
having a
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first mould inner opening extending at least partially into the first mould,
the
method comprises the steps of:
a) securely attaching a stretchable sheath to the first mould to impermeably
cover the first mould inner opening;
5 b) subsequent to the attaching, extending a retaining member through the
first mould inner opening into a retaining position to retain the structure
in the spaced relationship;
c) subsequent to the extending, distributing the settable mixture within the
space; and
d) before terminating the distributing, retracting the retaining member from
the space into a retracted position outside the space, the sheath being
smoothly aligned with the first mould inner surface and smoothly
bounding the space therewith when the retaining member is in the
retracted position, the sheath preventing a flow of the settable mixture
outside the space through the first mould inner opening.
In all aspects, sheath impermeably covers inner opening and is smoothly
aligned with first mould inner surface when retaining force and retaining
member are withdrawn. Thus, sheath advantageously prevents formation of
ridges and allows for formation of a product having a smooth outer surface,
without protrusions such as ridges, defined by first mould inner surface and
sheath.
BRIEF DESCRIPTION OF THE DRAWINGS
Further aspects and advantages of the present invention will become better
understood with reference to the description in association with the following
Figures, in which similar references used in different Figures denote similar
components, wherein:
Figure 1 is an outer perspective view of an embodiment of a spacer in
accordance with a first embodiment of the present invention;
Figure 2 is a side sectional view of the spacer shown in Figure 1, showing the
spacer fastened to a first mould;
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Figure 3 is a side sectional view of a spacer shown in Figure 1, showing a
plurality of spacers fastened to a first mould and circumferentially spaced
thereupon;
Figure 4 is an exploded view of the spacer shown in Figure 1, from an outer
perspective facing a fastening plate thereof;
Figure 5 is an exploded view of the spacer shown in Figure 1, from an inner
perspective facing a sheath inner surface thereof;
Figure 6 is an inner perspective view of the spacer shown in Figure 1; and
Figure 7 is a side perspective view of the spacer shown in Figure 1, showing a
plurality of spacers fastened in longitudinal alignment on a first mould.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
With reference to the annexed Figures an embodiment of the present invention
will be herein described for indicative purpose and by no means as of
limitation.
The invention in general will first be described and then an application of
the
invention for forming concrete products, including reinforced concrete pipes
having reinforcing metal mesh cages contained therein, will be illustrated.
Referring now to Figure 1, therein is shown an outer perspective view of a
spacer in accordance with an embodiment of the present invention, shown
generally as 10. Spacer 10 has fastening means, shown generally as 12,
which, in the embodiment, includes a fastening plate 14 that is securely
attached with fastening plate nuts 16 and fastening plate washers 18 to
fastening plate screws 20 that engage correspondingly spaced notches 22 in
fastening plate 14. Spacer 10 also has adjustment means, shown generally as
24, and which includes rods 26, for adjusting a spaced relationship maintained
by spacer 10.
To generally explain the functioning of spacer 10, reference is now made to
Figure 1 and Figure 2, a cross sectional view of spacer 10 shown in Figure 1.
Spacer 10 has retaining member 28 which is extendable from retracted position
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30 to retaining position 32 through first mould inner opening 34, which
extends
into first mould 36. First mould inner opening 34 is impermeably covered by
stretchable sheath 38 on first mould smooth inner surface 40 and, when sheath
38 is in retracted position 30, sheath inner surface is 42 smoothly aligned
with
first mould inner surface 40 and smoothly bounds space 44 therewith. A
settable mixture (not shown), such as concrete or the like, is distributed
into
space 44 for forming a product, not shown, made from the settable mixture and
having the shape of space 44. When in retracted position 30, retaining member
28 is integrally retracted from space 44 through first mould inner opening 34
and
maintains sheath 38, and particularly sheath inner surface 42, in smooth
alignment with first mould inner surface 40 across first mould inner opening
34.
When extended into retaining position 32, retaining member 28, enclosed by
sheath 38, is extended into space 44 by a retaining force which retaining
member 28 in turn exerts on sheath 38, thereby stretching sheath 38, and on
structure, shown generally as 46. Retaining force causes retaining member 28,
and therefore sheath 38, to engage structure 46 and retain structure 46 in a
spaced relationship 50 relative to first mould inner surface 40 to ensure that
structure 46 is correctly situated in the product formed during distribution
of the
settable mixture and containing structure 46. Specifically, spaced
relationship
50 refers to the distance between structure 46 and first mould inner surface
40.
Additional second mould 52 may be situated within space 44 and structure 46
between first mould inner surface 40 and second mould 52. Second mould may
be so situated to form a product having a hollow inner portion defined by
second
mould 52 and an outer product portion, not shown, shaped in the form of
reduced space 44a and containing structure 46 within outer product portion.
Sheath inner surface 42 is impermeable to settable mixture, as is first mould
inner surface 40. Sheath covers first mould inner opening 34 at all times
during
distribution of settable mixture in space 44. Thus, sheath 38 impermeably
separates retaining member 28 from space 44 when extended therein into
retaining position 32 by retaining force, thereby enveloping retaining member
28, and when retaining member 28 is in retracted position 30. It will be
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apparent to one skilled in the art that sheath 38 and first mould 36 may also
be
constructed such that all portions of each are impermeable to settable
mixture.
Reference is now made to Figure 2 in conjunction with Figure 3, a side
sectional
view of spacer 10 shown in Figure 1, showing a plurality of spacers 10
fastened
to first mould 36 and circumferentially spaced thereupon. When forming the
product, retaining member 28, enveloped by sheath 38, is extended into
retaining position 32 by retaining force and distribution of the settable
mixture
into space 44 is commenced. Retaining member 28 is maintained in retaining
position 32 by retaining force until the settable mixture is sufficiently
distributed
in space 44 and sufficiently set to retain structure 46 in the spaced
relationship
50 without further retaining by retaining member 28. Retaining member 28 is
then retracted into retracted position 30 and sheath 38, specifically sheath
inner
surface 42, is smoothly aligned with first mould inner surface 40. The sheath
inner surface 42 and first mould inner surface 40 thus form a smooth and
impermeable moulding surface and smoothly and impermeably outwardly bound
space 44.
Distribution of settable material continues during retraction into retracted
position 30 and while retaining member 28 is situated therein until
distribution of
settable mixture in space 44 is complete, i.e. when settable mixture is
distributed throughout space 44. Since sheath inner surface 42 is impermeable
to settable mixture and smoothly aligned with first mould inner surface 40
when
retaining member 28 is in retracted position 30, sheath 38 prevents flow of
settable mixture outside of space 44 through first mould inner opening 34.
Thus, sheath 38 prevents formation of protrusions, such as ridges, of settable
mixture or uneven distribution of thereof in any part of space 44 situated
adjacent to first mould inner opening 34. The smooth and impermeable
characteristics of first mould inner surface 40 also prevent formation of
protrusions and uneven distribution of settable mixture adjacent thereto.
Thus,
the product formed has the shape of space 44 and has a smooth outer product
surface matching that of the first mould inner surface 40 and the sheath inner
surface 42 which bound space 44. A possible distribution of a plurality of
spacers during product formation is shown in Figure 3.
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Referring now to Figures 2, 3, and 4, as with first mould inner surface 40 and
sheath inner surface 42, retaining member 28 has a smooth retaining member
inner surtace 54, which faces toward sheath 38. Since retaining member inner
surface 54 is also smooth, retaining member inner surface 54 prevents
formation of ridges in settable mixture in any part of space 44 adjacent
thereto,
including when retaining member 28 is retracted into retracted position 30. In
contrast, retaining member outer surface 56, situated generally opposite
retaining member inner surface 54 and facing away from sheath 38, has
retaining member protrusions 58 extending outwardly therefrom in a direction
away from sheath 38. Retaining member protrusions 58 are situated on
generally latitudinally opposite retaining member ends 60, which bound
retaining member central portion 62 of retaining member outer surface 56.
To show the details of the inner workings of spacer 10 and interconnecting
parts
thereof, reference is now made to Figures 2, 4, and 5. Extension of retaining
member 28 into retaining position 32 is effected by extension means, shown
generally as 64, which generates and applies retaining force to retaining
member 28 and sheath 38 to retain structure 46 in spaced relationship 50. In
the embodiment, extension means 64 is an air inflatable bladder 66 fixedly
mounted and enclosed in housing 68, which is immovably and fixedly mounted
within spacer 10. Specifically, housing 68 is mounted on fastening plate outer
surface 72 of fastening plate 14 with housing base ends 70 that are immovably
and fixedly connected to fastening plate outer surface 72. When retaining
member 28 is in retracted position 30, retaining member 28 is also situated in
housing 68, with retaining member protrusions 58 engaged in retaining member
protrusion sockets 74. Retaining member protrusion sockets 74 are disposed
on housing top inner surface 76, which faces bladder 66 and retaining member
28, and extend at least partially into housing top 78. It will be apparent to
one
skilled in the art that a variety of means, such as solder, screws, or the
like may
be employed for connecting housing 68 to fastening plate outer surface 72 and
it is not the intention of the inventor to impose any specific means or method
therefor.
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When in an extended configuration 80, i.e. when the bladder 66 is inflated
with
air, bladder 66 applies the retaining force upon retaining member 28 that is
directed toward structure 46. The retaining force, generated by the expansion
of bladder 66 by inflation thereof, extends retaining member 28 into retaining
5 position 30 and, since retaining member 28 is separated from space 44 by
sheath 38, causes sheath 38 to stretch into stretched configuration 82 as
retaining member 28 moves into retaining position 32. Retaining member 28 is
retained in retaining position 32 by the retaining force, and sheath 38
remains
stretched in stretched configuration 82 engaging structure 46 until bladder 66
is
10 placed in retracted configuration 84, i.e. when bladder 66 is deflated,
thus
withdrawing the air and the retaining force. As the retaining force is
withdrawn,
sheath 38 is no longer held in stretched configuration 82 thereby and
contracts
towards first mould inner surface 40, thereby applying a retracting force,
directed away from space 44, upon retaining member 28 that causes retaining
member 28 to retract back into retracted position 30.
Referring still to Figures 2, 4, and 5, bladder 66 is shaped and sized to be
engaged in a bladder cavity 86, extending from housing top inner surface 76
into housing top 78, when bladder 66 is in retracted configuration 82. Bladder
66 is fixedly and sealably mounted in housing 68 upon threaded bladder screws
88 extending from retaining member central portion 62 through axially aligned
bladder screw slits 90. Bladder screw slits 90 are situated on generally
latitudinally opposite bladder ends 92 of bladder 66 on first bladder surface
94,
facing retaining member 28, and generally opposite second bladder surface 96
Threaded bladder nut 98 and bladder washer 100 are mounted upon bladder
screws 88 and bladder nut 98 is turned thereupon towards second bladder
surface 96 to securely and sealably engage bladder washer 100 therebetween
upon second bladder surface 96, thus attaching bladder 66 to retaining member
28 and mounting bladder 66 in housing 68. Bladder screw receiver slots 102,
extending from housing top inner surface 76 and through housing top 78, are
axially aligned with bladder screw slits 90 and bladder screws 88 and are
sized
and shaped to receive bladder screws 88, bladder nuts 98, and bladder
washers 100 when retaining member 28 is returned to retracted position 30. As
shown, bladder screw 88 may be removably engaged in a bladder screw socket
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106 sized and shaped to engage bladder screw head 108. Bladder screw
sockets 106 extends through retaining member 28 and are in axial alignment
with bladder screw slits 90 and bladder screw receiver slots 102 and allows
bladder screws 88 to extend therethrough. Further, each bladder screw socket
106 and bladder screw head 108 are sized and shaped such that, when bladder
66 is attached with bladder screw 88, bladder screw head inner surface 110,
which faces sheath 38, is smoothly aligned with retaining member inner surface
54 and does not extend outwardly or inwardly therefrom. Alternatively, bladder
screws 88 may be permanently and fixedly incorporated into central portion 62
of retaining member 28.
It will be apparent to one skilled in the art that use of other extension
means 64
is possible. For example, bladder 66 could be inflated with water or could be
motorized. In addition, other means than bladder screws 88, bladder nuts 98,
and bladder washers 100, such as glue or sealant, may be contemplated for
mounting extension means 64, whether extension means 64 is a bladder 66 or
not, in spacer 10. It is not the intention of the inventor to limit the
extension
means 64 and the means used for mounting the extension means 64 to those
described specifically herein. It will be further apparent to one skilled in
the art
that other means than retaining member 28 may be used to apply retaining
force to sheath 38 and structure 46. It is not the intention of the inventor
to limit
the means by which retaining force may be transferred and applied upon sheath
38 and structure 46 to the retaining member 28 disclosed herein.
Referring again to Figures 2, 4, and 5, to ensure that retaining position 32,
and
therefore the spaced relationship 50, can be adjusted, spacer 10 also has
adjustment means, shown generally as 24. In the embodiment, adjustment
means 24 is comprised of axially movably mounted rods 26 attached to
retaining member 28 and having stopper means 112. More specifically, each
rod 26 is axially movably mounted in barrier means 114, which is a housing top
barrier plate 116 securely mounted upon housing top outer surface 104. Barrier
plate 116 is mounted upon housing top outer surface 104 with threaded barrier
plate screws 118 inserted through barrier screw openings 120 and extending
from barrier plate outer surface 122 through barrier plate inner surface 124
and
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removably and securely engaged in threaded barrier screw sockets 126
disposed in housing top 78. Barrier plate inner surface 124 faces housing top
outer surface 104 and is generally opposite barrier plate outer surface 122.
Barrier plate 116 has barrier plate rod openings 128 extending therethrough
and
into which rods 26 extend into housing 68 and which are axially aligned with
housing rod channels 130 extending through housing top 78, from housing top
outer surface 104 through retaining member protrusion sockets 74 and housing
top inner surface 76. Rod 26 is axially and movably mounted through barrier
plate rod openings 128 and housing rod channels 130, and rods 26 are
engaged at a longitudinal first rod end 132 of each rod 26 in rod sockets 134
on
retaining member 28. Thus, first rod end 132 is attached to retaining member
28. Longitudinal second rod end 136, which is generally opposed to first rod
end 132, has stopper means, generally shown as 112, mounted thereupon.
Barrier plate 116 and housing top 78 are thus situated between retaining
member 28 on first rod end 132 and stopper means 112 on second rod
end 136.
In the embodiment, stopper means 112 is a threaded movable adjustment nut
140 and adjustment washer 142 adjustably movably mounted on second rod
end 136, which is also threaded. Adjustment washer 142 is situated between
adjustment nut 140 and barrier plate outer surface 122 of barrier plate 116.
Each rod opening 128 in barrier plate 116 is of smaller dimension than
adjustment washer 142. Thus, adjustment washer 142 prevents passage of
adjustment washer 142 and adjustment nut 140 through rod opening 128, and,
therefore, through barrier plate outer surface 122 when adjustment washer 142,
specifically adjustment washer abutting surface 144 thereof, abuttingly
engages
barrier plate outer surface 122 towards which adjustment washer abutting
surface 144 faces. Thus, barrier plate 116 serves as a barrier preventing
passage of adjustment washer 142 and adjustment nut 140 through barrier
plate outer surface 122 towards sheath 38; the passage being stopped by
adjustment nut 140 and, more specifically, adjustment washer 142 which
abuttingly engage barrier plate 116.
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Threaded retaining screw 146 securely and releasably retains adjustment nut
140 in an adjustable adjustment position 148 corresponding to retaining
position
32 of retaining member 28 when retaining screw 146 is engaged in threaded
retaining screw socket 150. When retaining screw 146 is at least partially
disengaged from retaining screw socket 150, adjustment nut 140 may be moved
by turning adjustment nut 140 to adjust adjustment position 148 thereof.
When retaining member 28 is moved toward retaining position 32, first rod end
132 also moves toward retaining position 32 and second rod end 136 moves
toward barrier plate outer surface 122. Adjustment position 148 of adjustment
nut 140 is set such that, when retaining member 28 is in retracted position
30, a
first distance D1, not shown, between adjustment nut abutting surface 152,
facing adjustment washer 142, of adjustment nut 140 and housing barrier plate
outer surface 122 is equal to a second distance D2, not shown, between
retracted position 30 of retaining member 28 and retaining position 32 with
addition of third distance D3, not shown. Third distance D3 is the distance
between adjustment washer abutting surface 144 and generally opposite
adjustment washer outer surface 154. In other words, when the second
distance between retracted position 30 and retaining position 32 is D2, the
adjustment position 148 of adjustment nut 140 is set to respect the following
relationship, R1, for D1.
D1 = D2 + D3 (R1)
If the adjustment washer 142, which is optional provided that adjustment nut
abutting surface 152 is of greater dimension than rod openings 128, is not
used,
then adjustment position 148 of adjustment nut 140 is set to make first
distance
D1 and second distance D2 equal. In other words, the relationship between D1
and D2 is defined by the following relationship R2.
D1 = D2 (R2)
Thus, when retaining member 28 is moved to retaining position 32, adjustment
washer abutting surface 144 abuttingly engages barrier plate outer surface 122
preventing further movement of retaining member 28 into space 44 in the
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direction of structure 46. Alternatively, if adjustment washer 142 is not
used,
adjustment nut abutting surface 152 accomplishes this task. Thus, the
retaining
member 28 is stopped at retaining position 32. By adjusting the adjustment
position 148 of adjustment nut 140, the first distance D1 can be increased or
reduced, thus allowing for a corresponding increase or reduction in the second
distance D2 between retracted position 30 and retaining position 32. Since
retracted position 30 is fixed, adjustment of adjustable position of
adjustment
nut therefore increases or decreases the extension of retaining member 28 into
space 44 when in retaining position 32, thereby adjusting the retaining
position
32 and spaced relationship 50.
To ensure that movement of rods 26 is substantially axially aligned with
structure 46 and rod openings 128, spacer 10 has rod guiding means, namely
an insertable rod guide socket 156 inserted in rod channel 130. Rod guide
socket outer surface 158 is sized and shaped to securely and removably
engage rod channel inner surface 160, thus holding rod guide socket 156 in rod
channel 130 and allowing removal of rod guide socket 156 therefrom when
barrier plate 116 is removed. Rod guide socket inner surface 162, disposed
generally opposite rod guide socket outer surface 158 is sized and shaped to
substantially align with size and shape of rod 26 and allow rod to move
therein
in axial alignment with structure 46 and rod openings 128, thereby keeping
movement of rod 26 and retaining member 28 between retracted position 30
and retaining position 32 essentially straight and in axial alignment with rod
openings 128.
Inflation of bladder 66 is effected via inflation means, shown generally as
164,
externally accessibly disposed in an inflation means socket 166 which extends
integrally through housing top 78. In the embodiment shown, inflation means
164 is an air valve 168 for receiving air that is externally accessible in
inflation
means socket 166 from inflation means opening 170 in barrier plate 116 that is
axially aligned with inflation means socket 166. When air valve 168 is in an
open configuration, not shown, air may be introduced thereby into bladder 66,
for inflating bladder 66 into extended configuration 80, thereby generating
and
applying retaining force, or removed thereby from bladder 66, for deflating
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bladder 66 into retracted configuration 84, thereby withdrawing retaining
force.
Typically, to inflate bladder 66, air is introduced by connecting an air pump,
not
shown, to air valve 168, placing air valve 168 in the open configuration, and
pumping air through air valve 168 into bladder 66. To deflate bladder 66, air
5 pump is deactivated or removed and air valve 168 is placed in open
configuration. When valve is in closed position, not shown, air is retained in
bladder 66 and may not pass through air valve 168. Typically, air valve 168
will
be in closed position when bladder 66 is inflated into extended configuration
80
to maintain retaining member 28 in retaining position 32.
10 To better explain fastening of spacer 10 to first mould 36, reference is
now
made to Figures 2, 4, 5, and 6. As mentioned previously, spacer 10 is
releasably fastened to first mould 36 with fastening means 12, namely
fastening
plate 14, with fastening plate screws 20 engaged in correspondingly spaced
notches 22 of fastening plate 14. Threaded fastening plate nuts 16 and
15 fastening plate washers 18 are engaged upon fastening plate screws 20 and
fastening plate nuts 16 are turned towards fastening plate outer surface 72
adjacent to notches 22 for secure engaging fastening plate nuts 16 and washers
18 thereupon. Fastening plate 14 to is thus fastened to first mould 36 upon
first
mould outer surface 198, which is disposed generally opposite first mould
inner
surface 40. Fastening plate 14, and therefore spacer 10, can be removed by at
least partially disengaging fastening plate nuts 16 by turning them away from
fastening plate 14.
Fastening plate screws 20 protrude outwardly from first mould 36 beyond first
mould outer surface 198 and are securely engaged in insert plate 172, which is
fixedly inserted or otherwise incorporated into first mould 36 and securely
attached therein by soldering or other methods in insert plate opening 174 in
first mould 36. Insert plate inner surface 176, which faces space 44 and
defines
first mould inner opening 34 when insert plate 172 is inserted into insert
plate
opening 174, is smooth and is shaped to smoothly align with first mould inner
surface 40 and sheath 38 and smoothly and impermeably bounds space 44
therewith by forming part of the smooth and impermeable moulding surface.
Insert plate outer surface 178, disposed generally opposite insert plate inner
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surface 176, is sized and smoothly shaped to smoothly align with the shape of
first mould outer surface 198 and fastening plate inner surface 180. Fastening
plate screws 20 have fastening plate screw heads 182 which are engaged in
fastening plate screw sockets 184 having fastening plate screw openings 186
disposed on insert plate inner surface 176. Fastening plate screw heads 182
are sized and shaped to smoothly align with smooth lower insert plate surface
and smooth inner surface when inserted into fastening plate screw openings
186 and insert plate inner surface 176. Thus, insert plate inner surface 176
and
fastening plate screws 20 do not cause extrusions from the space 44 or
protrusions into space 44 and smoothly bound space 44 along with first mould
inner surface 40 and sheath 38.
To assist placement of fastening plate 14 on first mould outer surface 198,
first
mould outer surface 198 has protruding lips 188 attached thereto which are
shaped for aligning with corresponding fastening plate edges 190 of fastening
plate 14. When corresponding edges 190 are aligned with protruding lips 188,
fastening plate screws 20 are aligned with correspondingly spaced notches 22
such that fastening plate screws 20 protrude through notches 22 for
engagement with fastening plate nuts 16 and fastening plate washers 18.
Fastening plate 14 also has fastening plate opening 192 extending through
fastening plate inner surface 180 and which is sized and shaped to the contour
of retaining member 28, thereby allowing retaining member 28 to pass from
housing 68 through fastening plate 14 into space 44.
It will be apparent to one skilled in the art that fastening plate screws 20
may be
directly incorporated into first mould 36 without use of insert plate 172.
However, in such cases, fastening plate screws 18 must be incorporated into
first mould 36 such that fastening plate screws 20 do not create protrusions
into
or extrusions from first mould inner surface 40 to ensure that space 44
remains
smoothly bounded. Similarly, first mould inner opening 34 may be directly
disposed in first mould inner surface 40 and defined therein without use of
insert
plate 172. It is not the intention of the inventor to limit the means by which
fastening plate screws 20 may be incorporated into first mould 36 or to limit
fastening means 12 to the fastening plate 14 shown and described herein. It is
CA 02535722 2006-02-06
17
also not the intention of the inventor to limit the means in which first mould
inner
opening 34 may be defined to inclusion thereof in insert plate 172.
It will further be apparent to one skilled in the art that other means than
fastening plate screws 20, such as clamps, may be used to fasten fastening
plate 14 to first mould 36 and that, depending on the shape and the size of
first
mould 36 and fastening plate 14, one fastening plate screw 20 and one
correspondingly spaced notch 22 may be sufficient for fastening spacer 10 to
first mould 36. Also, again depending on size and shape of spacer 10 and first
mould 36, a single protruding lip 188 may be sufficient for aligning fastening
plate screws 20 with correspondingly spaced notches 22. Similarly, a single
rod
26 may also be sufficient for adjustment of retaining position 32 and spaced
relationship 50.
One skilled in the art will also note that other means than correspondingly
spaced notches 22, such as closed sockets, may be used for engagement of
fastening plate screws 20. It is not the intention of the inventor to limit
the
configuration of the fastening plate 14 to that shown and described herein.
Finally, one skilled in the art will realize spacer 10 may be directly and
fixedly
incorporated into first mould 36.
Optional back plate 194 is removably insertable into first mould 36 and
provides
additional support and contouring for maintaining alignment of sheath inner
surface 42 with shape of first mould inner surface 40 and, when insert plate
172
is present, insert plate inner surface 176. Back plate inner surface 196 faces
space 44 and sheath 38 and is smoothly shaped and sized to smoothly engage
sheath outer surface 200 which is disposed generally opposite sheath inner
surface 42. More specifically, back plate 194 is removably inserted into first
mould outer opening 202 which is aligned in shape and size with first mould
inner opening 34 and generally disposed opposite thereto. Thus retaining
member 28 may pass through first mould outer opening 202 and then through
first mould inner opening 34, the two openings 34, 202 essentially forming a
retaining member channel, not shown, to extend into retaining position 32.
Sheath 38 is inserted through first mould outer opening 202 to impermeably
cover first mould inner opening 34. When back plate is inserted into first
mould
CA 02535722 2006-02-06
18
outer opening 202, back plate inner surface 196 is located at an offset
position,
not shown, that is outwardly offset, towards first mould outer surface 198,
from
first mould inner surface 40 and insert plate inner surface 176 at a distance
equal to the thickness of sheath 38. Thus, back plate inner surface 196
smoothly reinforces sheath 38 across first mould inner opening 34 in the
contour and shape of first mould inner surface 40 and insert plate inner
surface
176. Back plate 194 thereby ensures that sheath inner surface 42 remains in
smooth alignment with first mould inner surface 40 and, when insert plate 172
is
present, insert plate inner surface 176 while impermeably covering first mould
inner opening 34.
Back plate 194, when inserted into first mould outer opening 202 and fastening
plate 14 is fastened upon first mould 36, is situated between fastening plate
14
and first mould inner opening 34. When fastening plate 14 is removed, back
plate 194 may be removed, allowing inspection, adjustment, and replacement of
sheath 38.
Back plate 194 has back plate opening 208 through which retaining member 28
may pass. Thus, retaining member 28 may pass through first mould inner
opening 34, or a portion thereof, i.e. back plate opening 208 when back plate
194 is inserted. Back plate opening 208 is axially aligned with fastening
plate
opening 192 and, like fastening plate opening 192, is sized and shaped to
closely match the size and shape of retaining member 28. Further, fastening
plate opening 192 and back plate opening 208 are positioned to be axially
aligned with each other and with rod openings 128 and rod guide socket 156.
Thus, fastening plate opening 192 and back plate opening 208 provide a
retaining member guiding means for further facilitating maintenance of
movement of retaining member 28 in axial alignment with rod openings 128.
Sheath 38 may be sealingly and impermeably attached to back plate 194 by a
sealing agent such as a polyurethane compound, or may be directly attached to
the edges of first mould inner opening 34. Alternatively, sheath 38 may be
held
in place by force applied by fastening plate 14 upon back plate 194 when
fastening plate 14 is fastened to first mould 36. Sheath 38 may also be larger
than back plate 194 and have a portion extending outside of first mould outer
CA 02535722 2006-02-06
19
opening 202 when back plate 194 is inserted. This excess portion may be held
between fastening plate inner surface 180 and back plate outer surface 210,
generally opposed to back plate inner surtace 196, when fastening plate 14 is
fastened to first mould 36. It will be apparent to one skilled in the art that
sheath
may be directly attached to mould without use of back plate 194 or that other
means than back plate 194 may be used for reinforcing sheath. It is not the
intention of the inventor to limit the scope of the invention to use of
backplate
194 as described herein.
Referring now to Figures 2, 3, and 7, an application of spacer 10 for forming
a
reinforced concrete products, such as a concrete pipes, having reinforcing
metal
mesh cage as structure 46 is now described. As shown, a plurality of spacers
10 are fastened to first mould 36, using fastening plate screws 20, engaged in
notches 22 on fastening plate 14, fastening plate washers 18 and fastening
plate nuts 16. During fastening with fastening plate 14 for each spacer 10,
protruding lips 188 facilitate alignment of fastening plate screws 20 with
correspondingly spaced notches 22.
Once spacers 10 are fastened to first mould 36 and metal mesh cage, i.e.
structure 46, is placed within reduced space 44a, retaining member is extended
into space 44 by extension means 64 which is placed in extended configuration
80. In other words, bladder 66 is inflated, perhaps with an air pump, not
shown,
using air valve 168 in open configuration as inflation means 168. Inflated
bladder 66 in extended configuration 80 applies a first force directed towards
structure 46, metal mesh cage, that extends retaining member 28 into retaining
position 32 and stretches sheath 38 into stretched configuration 82. Air valve
168 is then placed in closed position to retain air in bladder 66 and retain
retaining member 28 in retaining position 32. When all spacers 10 have
retaining members 28 in retaining position 32, structure 46, i.e. metal mesh
cage, is securely retained in spaced relationship 50 in space 44 with regard
to
first mould inner surface 40. Distribution of settable mixture, i.e. concrete,
is
then initiated. When concrete is sufficiently distributed and set to maintain
structure 46 in spaced relationship 50 without retaining by retaining member
28,
extension means 64 is placed in retracted configuration 84. In other words,
air
CA 02535722 2006-02-06
valve 168 is placed in open configuration and air is allowed to escape from
bladder 66 thereby, thus deflating bladder into retracted configuration 84.
First
force is therefore withdrawn and a second force, directed towards first mould
inner surface 40 moves retaining member 28 back into retracted position.
5 Distribution of concrete continues until concrete is completely distributed
within
space 44. Space 44, when retaining member 28 is in retracted position 30, is
smoothly outwardly bounded by first mould inner surface 40 and sheath inner
surface 42, as well as, when insert plate 172 and back plate 194 are present,
insert plate inner surface 176 and back plate inner surface 196, all surfaces
40,
10 42, 176, 196 forming a smooth moulding surface. Further, sheath 38 prevents
flow of concrete outside of space 44 through first mould inner opening 34.
Thus, when distribution of concrete is completed and concrete is sufficiently
set,
the concrete product so formed has a smooth outer concrete product surface
formed by surfaces 40, 42, 176, 196. In particular, outer concrete product
15 surface is smooth and without uneven ridges in any part of outer concrete
pipe
surface area in proximity to first mould inner opening 34.
Should the desired concrete product require a hollow section, such as in the
case of a reinforced concrete pipe, additional second mould 52 is inserted
prior
to distribution of concrete and surrounded by structure 46, i.e. the metal
mesh
20 cage. Second mould 52 therefore defines hollow portion of concrete pipe and
concrete is distributed within reduced space 44a. Second mould 52 also has a
smooth surface, thus insuring that the inner concrete surface of the product,
i.e.
the reinforced concrete pipe, formed thereby is also smooth.
For distributing concrete, a variety of methods and means may be employed,
including vibration of concrete, packerhead techniques for packing concrete in
space 44, or spinning. In addition, concrete may be substantially dry, such as
is
used in dry cast production of concrete products, or wet. It is not the
intention of
the inventor to limit the scope of the present invention to a given
distribution
method for any given settable mixture.
To show a possible distribution of spacers for manufacturing a reinforced
concrete product as described above, reference is again made to Referring to
Figures 3 and 4. As shown in Figure 3, for a product of ovular shape, such as
CA 02535722 2006-02-06
21
concrete pipe, using a first mould 36 having an ovular first mould inner
surface
40 and an ovular first mould outer surface 198, a plurality of spacers 10 may
be
equally circumferentially spaced on first mould outer surface 198. Also, as
shown in Figure 4, a plurality of spacers 10 may be placed in longitudinally
aligned on first mould outer surface 198. However, it will be apparent to one
skilled in the art that the quantity of spacers 10 required and their exact
placement will depend on the size and shape of the product. In general, the
quantity of spacers 10 required will increase with the size of the product.
Further, spacers 10 will be placed more closely together for smaller products.
The respective shapes of the product, first mould inner mould surface 40, and
first mould outer surface 198 will also influence the quantity of spacers 10
and
their placement. It is not the intention of the inventor to limit the quantity
and
placement of spacers 10 to that specifically illustrated therein.
One skilled in the art will also realize that the settable mixture used need
not be
concrete. In fact, spacer 10 may be used in the forming of any product
containing structure 46 in which a settable mixture is introduced into space
44 to
form the product. For example, product could also be a plastic pipe or
product.
Finally structure 46 need not be a metal mesh cage, but may be any structure
that must be contained in a product made of a settable mixture formed in a
space 44. It is not the intention of the inventor to limit the scope of the
invention
to any specific application, such as the manufacture of concrete pipes as
described herein. Further, it is not the intention of the inventor to limit
the
settable mixture to any specific materials, such as concrete, or to limit the
structure contained in the product to any specific structure, such as a metal
mesh cage.
While specific embodiments have been described, those skilled in the art will
recognize many alterations that could be made within the spirit and scope of
the
invention, which are defined solely according to the following claims.
